Android: KitKat introduced full-screen, Immersive mode apps -- but only a few apps support the feature. GMD Full Screen Immersive Mode is a free tool that hides the status bar and navigation bar in apps so you can better focus on what you're doing.
The app gives you a choice of hiding both the status bar and navigation bar at the same time, or you can also leave one or other of the bars visible if you like. If you opt to hide the status bar you can avoid the constant stream of notifications you probably receive.
You can configure settings on a per-app basis, and while a notification appears to let you know that immersive mode is about to be activated, this can be removed with an in-app purchase.
The advantage of GMD Immersive Full Screen Mode is that it works with just about any Android handset running KitKat or Android L, no need for root. If you are rooted and use Xposed, click the link below for details of the Immerse Me Xposed module which includes similar full-screen options.